Kinetics of Phosphorus Sorption in Vegetative Treatment Area Soils

Vegetative treatment systems have been proposed and are being utilized to treat runoff from animal feeding operations. These systems use soil and vegetation to remove contaminants (solids, phosphorus, and nitrogen) from the feedlot runoff water and limit potential impacts runoff could have on water quality. Research has shown that these systems soils play a key role in retaining the phosphorus. Thus, the purpose of this experiment was to determine the rate of phosphorus sorption by the soil and in so doing evaluate the impact the runoff contact time with the soil has on phosphorus removal from the solution and retention in the soil. In this experiment, a phosphorous solution of 100 mg P/L, taken to approximate concentrations in the feedlot runoff, was added to soil samples obtained from three different locations in Iowa. After adding the phosphorous solution to each soil sample, the sample was continuously mixed and a sample of solution collected at 0, 1, 2, 4, 7, 14, 21 and 28 days to measure the amount of phosphorus remaining in solution. The results indicated that in most cases phosphorus was quickly sorbed as equilibrium was reached within approximately 24-hours. This indicates that relatively short contact times are required to phosphorus removal; however, in several cases phosphorus removal occurred more slowly and might place a limit on appropriate application rates. The results indicated that phosphorus sorption generally occurred more quickly in VTA soils than in the grass soil samples. Based on the measured sorption parameters, VTA areas ranging from 0.5 – 2.25 hectares are required per hectare of feedlot area

Impact of fiber source and feed particle size on swine manure properties related to spontaneous foam formation during anaerobic decomposition

Foam accumulation in deep-pit manure storage facilities is of concern for swine producers because of the logistical and safety-related problems it creates. A feeding trial was performed to evaluate the impact of feed grind size, fiber source, and manure inoculation on foaming characteristics. Animals were fed: (1) C–SBM (corn–soybean meal): (2) C–DDGS (corn–dried distiller grains with solubles); and (3) C–Soybean Hull (corn–soybean meal with soybean hulls) with each diet ground to either fine (374 μm) or coarse (631 μm) particle size. Two sets of 24 pigs were fed and their manure collected. Factors that decreased feed digestibility (larger grind size and increased fiber content) resulted in increased solids loading to the manure, greater foaming characteristics, more particles in the critical particle size range (2–25 μm), and a greater biological activity/potential

Using Total Solids Concentration to Estimate Nutrient Content of Feedlot Runoff Effluent from Solid Settling Basins, Vegetative Infiltration Basins, and Vegetative Treatment Areas

Increased environmental awareness has promoted the need for improved feedlot runoff control. The use of vegetative treatment systems (VTSs) to control and treat feedlot runoff may enhance environmental security and protect water quality. Knowledge of effluent nutrient concentrations throughout the vegetative treatment system is required to evaluate impact on water quality and system performance. Previously collected VTS monitoring data has provided the opportunity to investigate relationships between effluent quality parameters. The objective of this study was to evaluate, through correlation and regression, the relationships between total solids, nutrients, and effluent quality indicator concentrations of feedlot runoff at various stages of treatment in a VTS, including solid settling basin, vegetative infiltration basin, and vegetative treatment area effluent. Results of a correlation and primary factor analysis showed that most of the parameters’ concentrations were strongly correlated to each other, with a single factor capable of describing more than 60% of the variability of monitored parameters. Regression equations were developed to relate nutrient content and effluent quality indicator concentrations to total solids concentrations. Results were satisfactory for most parameters, indicating that total solids concentrations provided significant insight into VTS performance relative to nutrient concentration and effluent quality indicators. A comparison between predicted, based on total solids content, and monitored mass release of the parameters was conducted. No statistical difference was found for most parameters; indicating that effluent volume release along with total solids concentrations can be used to provide an estimate of nutrient mass in solid settling basin, vegetative infiltration basin, and vegetative treatment area effluent

Development of Regional Supply Functions and a Least-Cost Model for Allocating Water Resources in Utah: A Parametric Linear Programming Approach

The development and allocation of the water resourcse within a state require water planners to prepare plans far in advance of the actual time new facilities are required. It is not easy to identify and evaluate all the possible alternatives for providing water which incorporate broad objectives such as economic efficiency, social welfare, regional development, recreation benefits, and conservation of environment. Water resources development entails the modification of a natural hydrologic system to better meet man\u27s needs. The interrelationships among elements of the hydrologic system to better meet man\u27s needs. The interrelationships among elements of the hydrologic system are relatively simple in comparison to the social, legal, economic, and institutional interdependencies involved. The relationships are so complex as to require that planning of water resource development be accomplished on a systems basis. It has become apparent that water resource planning must consider mass transfer of water encompassing areas which have potential for economic growth competing with other areas already highly developed economically. The wisest political decisions and the greatest benefit to the public will result if a method is used to explore the probable consequences of alternative water resources development and management policies and plans. The objective of this study is to extend the capability of systems analysis and operations research to the problem of interregional planning of water resources allocation for the State of Utah. The hydrologic characteristics and cost of water in each of the ten hydrologic study units of the state were determined. Hydrolgoci data from hydrologic inventories and estimates from the Utah Division of Water Resources were used to determine availability, reservoir storage-draft relationships, evaporation loss from reservoirs, agricultural use return flow, and municipal and industrial use return flow. Cost data were developed for storage facilities, diversion and canal works, artificial recharge facilties, treatment of waste water, and treatment of municipal supply. Supply functions for water in each of the ten hydrologic study units of the state were determined. Two sets of functions were developed--one for agricultural use and one for municipal and industrical use. Parametric linear programming was employed to develop a function map of the shadow price (marginal cost) of water for each of the two uses. The shadow price of imported water (value) to each of the study units was also determined to show the possible economic consequences of inter-basin transfers. In general, imported water was of little or no value if water presently being evaporated from Great Salt Lake is available for diversion upstream. A statewide model was developed to determine a least-cost allocation of water resources to meet projected requirements. This linear programming allocation model was developed subject to constraints such as hydrologic characteristics, limits on inter-basin transfers, limits on artificial groundwater recharge, and existing water requirements. Parametric programming was utilized to determine the impact of changing availability which reflects policies regarding inflow requirements of the Great Salt Lake and interstate agreemetns, increased agricultural use and municiapl and industrical use which reflects population increases projected for the future and changing groundwater availability which reflects legal constraints. The primary facotr affecting inter-basin transfer of Colorado River water is the degree to which evaporation from Great Salt Lake is reduced